The report said there were 360 serious or sentinel events across all the district health boards (DHBs) in the last year, down 3 per cent on the previous year.

About a third were clinical management failings - including 17 serious delays in treatment, up on 13 the previous year and eight the year before that.

The commission said it was probable the number of reported delays represented just a small fraction of all cases because many fell below the reporting threshold.

The cases not only illustrated weaknesses in patient management and communications systems, but also failings in the amount of say that patients have over their own care.

The commission's reportable events clinical head, Dr David Sage, said the cases emphasised how important it was for clinicians to follow up when tests were ordered, referrals were made, or further treatment was recommended.

He said the commission was looking at measures which could reduce the likelihood of delays.

"For example, making sure patients are full partners in the management of their care - so they too are aware if there needs to be a further test, result from a specimen, or referral to another specialist."

Commission chairman Professor Alan Merry said not all the serious events described in the report were preventable, but many involved errors that should not have happened.

"In some tragic cases errors resulted in serious injury or death. Each event has a name, a face and a family, and we should view these incidents through their eyes."

He said the overall decrease in serious events showed DHBs had put in a lot of hard work to both report and prevent adverse events.

"At the same time, however, we have seen an increase in the number of cases of delayed treatment and suspected inpatient suicides."

There were 17 suspected inpatient suicides in the last year, up from three the previous year, but Dr Merry said they did not appear to be part of an increasing trend.

"The commission has looked at the reviews into these very sad events and there appear to be no common factors. There is also no evidence of a trend of increasing inpatient suicides."

Most of the cases involved mental health patients, although at least two were patients who had been on general wards.

The commission was working with the mental health sector to identify the best approach to reviewing and reporting on suicides involving mental health service users, and in future will issue a separate report on those events.

The latest report also highlighted a decrease in the number of falls, which make up almost half of all serious events reported by DHBs.

There were 170 serious falls in the last year, a 13 per cent decrease from the 195 falls the previous year.